painaputchi

I don't think it could be Obaketchi though, because the white triangular thing on his head is part of its character (it's a constant symbol for the Japanese to represent ghosts). Then if you look closely it has a pointy tail, like a devil one! That's why I thought it had to do with Devilgotchi. XD

painaputchi

Hey guys I finally found it!!! I think you were right!! It's a sort of "evil Tama-spirit": it appeared few minutes ago on my ID-L, haunting my poor Painaputchi who had to go to the Tama-Hospital! Thanks everyone!

Now the topic can be closed because I've had an answer... I just have to figure out how to do so! XD

Edit: mmmh... there's that Marked Solved thing.... do I have to mark my reply as "best answer"?? .-.